I do not normally like Sci-Fi but I loved this movie. Most importantly 2hours 40 minutes FLEW by. I agree with some of the other reviewers the plot itself was predictable but the special affects are amazing.
We took our 6 and 8 year old boys. They did NOT move the entire time - that should say it all there! I don't understand why it was PG-13. There is some language but it was definitely not every other word. There was maybe 1 scene of kissing which was nothing. And, yes, there is violence, but there is no gory blood shots.